Fringe projection for in-line inspection
AssigneeLMI Technologies Inc.
InventorsTerence Arden, Robert Loewen, Oleksiy Gukov
Life of this patent
Estimating the term…
Abstract
A structured light pattern comprising at least two sub-patterns in the direction of motion are projected onto an object during in-line inspection. Images of the object are captured for each sub-pattern. The sub-patterns are used to establish correspondence and to construct a profile using dense per pixel camera-projection correspondence.
Claims17
A method for determining three-dimensional coordinates of a plurality of object points of an object, said object moving in a direction of motion along an inspection path in an in-line inspection system, comprising:
- projecting onto said path structured light forming a two-dimensional pattern, said two-dimensional pattern being such that any one-dimensional slice of said pattern in the direction of motion is unique within said pattern, said two-dimensional pattern comprising at least two linear sub-patterns disposed in parallel within said two-dimensional pattern, each of said at least two linear sub-patterns varying in intensity only along a direction that is orthogonal to the direction of motion;
- capturing temporally sequential images of said structured light as reflected from said object points as said object moves along said path, so as to produce, for each of said object points, at least one image of each of said sub-patterns;
- analyzing said images to:
- determine correspondence between the images in relation to each of said object points by reference to at least a plurality of said sub-patterns;
- and,
- determine three-dimensional coordinates for each of said object points.
An optical three-dimensional scanning system comprising:
- a conveyor for conveying an object in a direction of motion along an inspection path in an in-line inspection system;
- at least one projector configured to project onto said path structured light forming a two-dimensional pattern, said two-dimensional pattern being such that any one-dimensional slice of said pattern in the direction of motion is unique within said pattern, said two-dimensional pattern comprising at least two linear sub-patterns disposed in parallel within said two-dimensional pattern, each of said at least two linear sub-patterns varying in intensity only along a direction that is orthogonal to the direction of motion;
- at least one camera coupled to said at least one projector and configured to capture temporally sequential images of said structured light as reflected from said object as said object moves along said path, so as to produce, for each of a plurality of object points of interest, at least one image of each of said sub-patterns;
- a processor coupled to said camera to determine correspondence between said temporally sequential images by reference to at least two of said sub-patterns and to determine three-dimensional coordinates of said object points of interest.
Dependencies are inferred from the claim text.